Novel synthetic caustic composition

ABSTRACT

An aqueous caustic composition comprising: a caustic component; an alkanolamine additive adapted to provide an extended buffering effect to the caustic composition when such is exposed to acid; and water. Uses and methods of using such compositions are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Canadian Patent Application No.2,985,622 filed Nov. 15, 2017, the entire contents of which areincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention is directed to a novel synthetic causticcomposition, more specifically a novel composition comprising a causticcomponent and an additive adapted to provide an extended and linearbuffering effect.

BACKGROUND OF THE INVENTION

Caustic compositions have a wide variety of uses in the oil and gasindustry. They can be used for pH control in aqueous solutions as wellas to control alkalinity. Caustic compositions also find other varieduses which includes, among others, breaking down of organic matter andremoving various impurities in the refining stage of petroleumproduction. The impurities it can be most effectively used to removeinclude carbon dioxide and various sulfur-containing compounds. Removalof sulfur-containing compounds is also referred to in the industry assweetening the petroleum. Some hydroxides can be highly hazardousmaterials to handle because they are very hygroscopic and typically havea high exothermic reaction with other fluids, especially low pH fluids.Sodium hydroxide is soluble in water, ethanol and methanol. Thesesolutions can cause severe, irreversible dermal/ocular burns. Sodiumhydroxide may cause chemical conjunctivitis and corneal damage. Severeeye burns with clouding of the surface, and ensuing blindness may occurfrom exposure to liquid sodium hydroxide. Low concentration levels ofmists or aerosols cause burning discomfort, spasmodic blinking orinvoluntary closing of the eyelids, redness, and tearing. At roomtemperature sodium hydroxide is a white crystalline, odorless,deliquescent solid, which absorbs moisture from the air. When sodiumhydroxide is dissolved in water, often a mist is formed. Sodiumhydroxide itself is nonflammable, but in contact with moisture it mayignite combustibles. Toxic fumes may be formed upon heating. The solid,solutions, mists, and aerosols are all corrosive.

Sodium hydroxide (widely utilized) is available commercially in a solid(sodium hydroxide is most commonly sold as flakes, prills, and castblocks) or a liquid solution (normally a 50% strength). Typically, in anoil & gas drilling application a solid bead or flake is added to amixing barrel with water until solubilized and then added to the mudsystem or fluid system to increase the pH for various reasons, such asto limit the precipitation of calcium and magnesium from a hard watersource, limit the incompatibility of the fluid system with formationclays/shales and reduce swelling. Another advantage of a liquid sodiumhydroxide is the liberation of hydrogen sulfide and carbon dioxide gasesfrom a fluid system. Having an alternative product that is lower hazardand more environmentally responsible is advantageous due to the highlevel of human exposure, and the fact that drill cuttings (that haveresiduals of the mud system) are often spread over agricultural fieldsas a disposal technique.

A 50% sodium hydroxide solution is widely utilized in the bitumenextraction process with relation to oil-sands development. Mostcommercial mineable oil sands producers use an extraction method “ClarksHot Water Extraction” process which was developed in the 1920s. One ofthe major operational disadvantages of a 50% sodium hydroxide solutionis that it begins to freeze at −13 degrees Celsius and a 25% solutionwill freeze at −17 Celsius. It is therefore advantageous to have aproduct with a much lower freeze point, as low as −20 Celsius. As thewaste fluids are intentional or unintentionally released into theenvironment post treatment, having a product that is moreenvironmentally responsible, low toxicity and lower hazard to handle ishighly advantageous. Volumes in excess of 200,000 gallons/day areutilized in the Canadian Oil Sands, and the technical and environmentaladvantages for a product with these constituents are substantial.

Alkaline Surfactant Polymer (ASP) flood applications utilize a high pHfluid to aid in reservoir recovery. Having a product that isnon-hazardous is an advantage. ASP formulation typically consists ofabout 0.5-1% alkali, 0.1% surfactant and 0.1% polymer. The alkalinecomponent reacts with the acidic moieties that exist in the oil creatingnatural soap and also helps reduce the adsorption of the surfactant onthe rock.

Borate crosslinked gel fracturing fluids utilize borate ions tocrosslink the hydrated polymers and provide increased viscosity. Thepolymers most often used in these fluids are guar and HPG. The crosslinkobtained by using borate is reversible and is triggered by altering thepH of the fluid system (increasing the pH generates the crosslinkfunction, decreasing the pH eliminates the crosslink). The reversiblecharacteristic of the crosslink in borate fluids helps them clean upmore effectively, resulting in good regained permeability andconductivity.

Some of the major challenges faced in the oil & gas industry withrespect to the use of conventional hydroxides include the following:high levels of corrosion on certain metals which are typically counteredby the use of High Density Polyurethane (HDPE) components, intensive andexpensive maintenance schedules—environment and equipment; reactionsbetween hydroxides and various types of metals can vary greatly but withcertain metals, such as aluminum, effects are substantial causingimmediate damage. As caustics are utilized to control pH levels in manysystems throughout the life cycle of a well, exposure to these metalscan happen often resulting in substantial replacement costs. Thisrenders typical hydroxide blends as controlled in most jurisdictions andrequire extensive labeling/handling and transportation procedures whichcan add to the end user costs. Additionally, the high toxicity levels ofhydroxides render them banned in many offshore operations due toconcerns over unintentional release into sensitive ocean ecosystems.

Like other highly corrosive alkalis, sodium hydroxide solutions candecompose proteins and lipids in skin, eyes or other living tissues viaamide hydrolysis and ester hydrolysis, which consequently causeschemical burns and may induce permanent blindness if it contacts eyetissue. Solid alkali may also express its corrosive nature if there iswater present on the skin or in the eyes. Sodium hydroxide is corrosiveto several metals, like aluminum which reacts with the alkali to produceflammable hydrogen gas on contact. Having an alternative that is muchless corrosive to metals, has a far lower freeze point, has a linear pHcontrol effect and provides a period of human dermal tissue protectionis advantageous. Having one of these advantages is desirable, havingmore than one is even more so.

The inherent environmental effects (organic sterility, poisoning ofwildlife etc.) of caustics in the event of an unintended/accidentalrelease on surface or downhole into water aquifers or sources of waterare devastating which can cause significant pH increase of such and cansubstantially increase the toxicity and could potentially cause a massculling of aquatic species and potential poisoning of humans/livestockand wildlife exposed to/or drinking the water. An unintended release atsurface can also cause damaging fumes to be released, potentiallyendangering human and animal health. This is a common event at largestorage sites when tanks split or leak. Typically, if near the public,large areas need to be evacuated post event.

The inability for many caustics and blends of such to biodegradenaturally without irreversibly damaging the soil, results in expensivecleanup-reclamation costs for the operator should an unintended releaseoccur. Moreover, the fumes produced by many bases are harmful tohumans/animals and are highly corrosive and/or explosive potentially,transportation and storage requirements for liquid bases are restrictiveand taxing in such that you must typically haul the products in tankersor intermediate bulk containers (IBC) that are rated to handle suchcorrosive-regulated products, creating exposure dangers for personnelhaving to handle them. Sodium hydroxide and its solutions, mists, andaerosols are rapidly damaging when they come in contact with the eyes,skin, and upper respiratory tract causing irritation, burns, coughing,chest pain and dyspnea. Swelling of the throat and accumulation of fluidin the lungs (shortness of breath, cyanosis, and expectoration) mayoccur. Ingestion of sodium hydroxide can cause severe corrosive injuryto the lips, mouth, throat, esophagus, and stomach. There is no antidoteto be administered to counteract the effects of sodium hydroxide.Treatment consists of supportive measures.

Price fluctuations with typical commodity caustics based on industrialoutput causing end users an inability to establish long term costs intheir respective budgets; severe reaction with dermal/eye tissue; majorPPE requirements (personal protective equipment) for handling, such ason site shower units; extremely high corrosion rates, the need forconstant expensive heating of liquid solutions and the aggressivenon-linear raising of pH are some of the negatives to the industrystandard bases utilized, such as sodium hydroxide.

When used to control the pH levels on surface of water/fluid systems,caustics are exposed to humans and mechanical devices as well asexpensive pumping equipment causing increased risk for the operator andcorrosion effects that damage equipment and create hazardous hydrogengas when they come into contact with water or aluminum. When mixed withacidic or lower pH fluids, caustics will create a large amount ofthermal energy (exothermic reaction) causing potential safety concernsand equipment damage, caustics typically need to be blended with freshwater to the desired concentration requiring companies to sometimespre-blend off-site as opposed to blending on-site, greatly therebyincreasing costs associated with transportation.

Typical caustics used in a pH control situation can or will causedegradation of certain polymers/additives/systems/formations requiringfurther chemicals to be added to counter these potentially negativeeffects, many offshore areas of operations have very strict regulatoryrules regarding the transportation/handling and deployment of causticscausing greatly increased liability and costs for the operator. Causticsor high pH fluids, such as caustic water can be destructive to manytypical elastomers found in the oil & gas industry such as blow outpreventers (BOP's)/downhole tools/packers/submersible pumps/seals,surface pumps and tank equipment etc., having to deal with high pHfluids during the back flush/disposal process is also very expensive.

Caustics perform many actions in the oil & gas industry and areconsidered necessary to achieve the desired production of variouspetroleum wells, maintain their respective systems and aid in certainfunctions (i.e. suppressing calcium & magnesium in hard waters). Theassociated dangers that come with using caustics are expansive andtasking to mitigate through controls whether they are chemically ormechanically engineered.

Eliminating or even simply reducing the negative effects of causticswhile maintaining their performance level is a struggle for theindustry. As the public demand for the use of cleaner/safer/greenerproducts increases, companies are looking for alternatives that performthe required function without all or most of the drawbacks associatedwith the use of caustics.

U.S. Pat. No. 7,073,519 discloses a facility parts cleaning compositionfor the processing of (meth)acrylic acid and/or (meth)acrylic esterscomprising an alkali metal hydroxide solution, a water-soluble aminoacid, N,N′-methylene bisacrylamide, and azobisisobutyronitrile, and acleaning method using the cleaning solution composition. Disclosed arecompositions including 5 to 50 wt % of at least one alkali metalhydroxide selected from the group consisting of sodium hydroxide andpotassium hydroxide, 0.01 to 1 wt % of a water-soluble amino acid, 0.001to 0.05 wt % of N,N′-methylene bisacrylamide, and 0.001 to 0.05 wt % ofazobisisobutyronitrile.

US Statutory Invention Registration no. H468 entitled “Alkalinehard-surface cleaners containing alkyl glycosides” discloses a cleaningcomposition comprising: (a) about 0.1 to 50 weight percent alkali metalhydroxide or ammonium hydroxide; (b) about 0.1 to 40 weight percentalkyl glycoside; and (c) about 10 to 95 weight percent water.

U.S. Pat. No. 6,387,864 discloses a laundry detergent compositioncomprising about 1 to about 75 parts by weight of at least one causticcompound, about 0.5 to about 50 parts by weight of at least one nonionicsurfactant, about 1 to about 35 parts by weight of at least one primaryamine compound.

U.S. Pat. No. 5,804,541 discloses a floor stripper composition isprovided, having a pH-value above 9.0, and comprising a soap, water anda glycine-N,N-diacetic acid compound, which is preferably methylglycinediacetic acid (MGDA). The diacetic acid is desirably in the form of adivalent metal complex thereof. The description states that a good floorstripper performance could be obtained with this composition owing toits low foaming behaviour.

U.S. Pat. No. 9,399,589 B2 teaches the use of glycine in the making of asynthetic base that is said to obviate all the drawbacks of strong basessuch as sodium hydroxide. It is stated that the compound is made bydissolving glycine in water and adding calcium hydroxide at a molarratio of about 1:1. Sodium percarbonate is then dissolved in thesolution to produce the new compound.

Since several operations in the oil industry expose fluids and equipmentto very high temperatures (some upward of 200° C.), the causticcompositions used in these various operations need to withstand thesehigh temperatures without losing their effectiveness. These compositionsmust be capable of being used in operations over a wide range oftemperatures while not affecting the equipment or people it comes incontact with.

Consequently, there is still a need for compositions for use in the oilindustry which can be used over a range of applications which candecrease a number of the associated dangers/issues typically associatedwith caustic applications to the extent that these caustic compositionsare considered much safer for handling on worksites. The presentinvention seeks to overcome some of drawbacks of the prior art causticcompositions and methods using such caustic compositions.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda caustic composition comprising:

-   -   a caustic component;    -   an alkanolamine additive adapted to provide an extended (more        methodical and linear) buffering effect to the caustic        composition as well as greatly lowering the freeze point and        providing an increased level of dermal protection; and    -   water

Preferably, the caustic component is selected from the group consistingof: potassium hydroxide; sodium hydroxide; lithium hydroxide; cesiumhydroxide; and combinations thereof. Calcium hydroxide is less desirableto use as it displays low stability and a strong tendency to precipitateout of solution. More preferred caustic component is selected from thegroup consisting of: sodium hydroxide and potassium hydroxide.Preferably, the caustic component is present in a concentration of up to40 wt % of the composition. Preferably also, the caustic component ispresent in a concentration ranging from 5 to 40 wt % of the composition.More preferably, the caustic component is present in a concentrationranging from 10 to 30 wt % of the composition. Even more preferably, thecaustic component is present in a concentration ranging from 15-25 wt %of the composition. Yet even more preferably, the caustic component ispresent in a concentration of approximately 25 wt % of the composition.

Preferably, the main components in terms of volume and weight percent ofthe composition of the present invention comprise strong base, such asNaOH, KOH, LiOH, CsOH, RbOH and an alkanolamine additive. Analkanolamine according to the present invention contains at least oneamino group, —NH₂, and one alcohol group, —OH.

Preferred alkanolamines according to the present invention include, butare not limited to, monoethanolamine, diethanolamine, triethanolamine,aminomethyl propanol, propanolamine, dimethylethanolamine,N-methylethanolamine. More preferred are monoethanolamine,diethanolamine. Most preferred is monoethanolamine.

When adding an alkanolamine to a strong base, there is the formation ofan adduct which greatly reduces the hazardous effects of the sodiumhydroxide on its own, such as the fuming effect, the hygroscopicity, andthe highly corrosive nature. The excess nitrogen can also act as acorrosion inhibitor at higher temperatures.

The molar ratio of the two main components can be adjusted or determineddepending on the intended application and the desired solubilizingability. According to a preferred embodiment where the caustic is NaOH,one can increase the ratio of the NaOH component to increase thesolubilizing ability of the composition while still providing at leastone of the following advantages: health; safety; environmental; andoperational advantages over sodium hydroxide.

While an alkanolamine such as monoethanolamine is a compound known bythe person of ordinary skill in the art, the latter knows that such acompound is not to be mixed with a strong base such as NaOH. In fact,the person skilled in the art will note upon review of the DOW safetydata sheet for monoethanolamine LFG 85 that it indicates that one mustavoid contact of this compound with strong bases.

Preferably, the additive is present in a concentration ranging from 2 wt% to 25 wt % of the composition. More preferably, additive is present ina concentration ranging from 4 wt % to 15 wt % of the composition. Yeteven more preferably, the additive is present in a concentration rangingfrom 4 wt % to 10 wt % of the composition.

According to another aspect of the present invention, there is provideda method of fracking a hydrocarbon-bearing formation using a crosslinkedpolymer gel, said method comprising the steps of:

-   -   providing a hydrocarbon-bearing formation;    -   providing a polymer;    -   providing a cross-linking activator and adding such to the        polymer;    -   adding to the polymer mixture a caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended and            more linear buffering effect to the caustic composition when            such is exposed to the fluid system; and        -   water;    -   adding a proppant to the resulting polymer mixture; and    -   injecting said resulting polymer-proppant composition into the        formation.

Preferably, the caustic component is present in amount of up to 50 wt %of the caustic composition.

Preferably, the crosslinking component is a borate ion or a zirconateion. Preferably, the polymer is a guar gum, Carboxymethyl guar gum,Hydroxymethyl guar gum; Hydroxypropylethyl guar gum;O-carboxymethyl-O-hydroxypropyl guar gum (CMHPG); Ammonium hydroxylpropyl trimethyl chloride of guar gum; O-carboyxymethyl-O-2hydroxy-3-(trimethylammonia propyl) guar gum (CMHTPG); Acryloyloxy guargum; Methacryloyl guar gum; Guar gum esters such as Hydroxy Propyl Guar(HPG), Carboxy Methyl Guar (CMG), Carboxy Methyl Hydroxy Propyl Guar(CMHPG), and Guar.

According to another aspect of the present invention, there is provideda method of removing impurities present in petroleum during the refiningthereof, said method comprising the steps of:

-   -   providing a petroleum product to be refined;    -   providing a caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended and            more linear buffering effect to the caustic composition when            such is exposed to acid; and        -   water;    -   adding said caustic composition to said petroleum product to be        refined; and    -   allowing said caustic composition and petroleum product to be        refined to remain in contact with one another for a period of        time determine to be sufficient for the sufficient removal of at        least one of carbon dioxide and sulfur-containing compounds.

According to another aspect of the present invention, there is provideda use of a composition according to a preferred embodiment of thepresent invention for the control the pH of water-based drilling fluids.

According to another aspect of the present invention, there is provideda use of a composition according to a preferred embodiment of thepresent invention for the breaking down of organic matter present inpetroleum during the refining thereof.

According to another aspect of the present invention, there is provideda use of the composition according to a preferred embodiment of thepresent invention for the removal of various impurities during therefining stage of petroleum production. Preferably, the impurities areselected from the group consisting of: include: carbon dioxide andsulfur-containing compounds.

According to another aspect of the present invention, there is providedan aqueous caustic composition comprising:

-   -   a caustic component;    -   an alkanolamine additive adapted to provide an extended        buffering effect to the caustic composition when such is exposed        to acid; and    -   water;        wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the additive are present in a molar ratio ranging from 15:1 to        5:1.

Preferably, the caustic component and the alkanolamine additive arepresent in a molar ratio ranging from 12:1 to 8:1. Preferably also, thecaustic component comprises a hydroxide anion and a monovalent cation.

According to another aspect of the present invention, there is provideda use of a buffered caustic solution in water treatment, wherein saidbuffered caustic solution comprising:

-   -   a caustic component;    -   an alkanolamine additive adapted to provide an extended        buffering effect to the caustic composition when such is exposed        to acid; and    -   water;    -   wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the alkanolamine additive are present in a molar ratio ranging        from 15:1 to 5:1;

According to another aspect of the present invention, there is provideda method to treat water, wherein said method comprises the steps of:

-   -   providing an aqueous caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended            buffering effect to the caustic composition when such is            exposed to acid; and        -   water;    -   wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the alkanolamine additive are present in a molar ratio ranging        from 15:1 to 5:1;    -   exposing a water requiring treatment to a pre-determined amount        of said caustic composition for a period of time sufficient to        effect the treatment intended.

BRIEF DESCRIPTION OF THE FIGURES

The invention may be more completely understood in consideration of thefollowing description of various embodiments of the invention inconnection with the accompanying figures, in which:

FIG. 1 depicts a caustic titration curve of NaOH (25 wt %) with noadditive; and

FIG. 2 depicts a titration curve of a composition according to apreferred embodiment of the present invention, said compositioncomprising NaOH (25 wt %) and 5 wt % MEA.

DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

Borate crosslinked gel fracturing fluids utilize borate ions tocrosslink the hydrated polymers and provide increased viscosity. Thepolymers most often used in these fluids are guar and HPG. The crosslinkobtained by using borate is reversible and is triggered by altering thepH of the fluid system (increasing the pH generates the crosslinkfunction, decreasing the pH eliminates the crosslink). The reversiblecharacteristic of the crosslink in borate fluids helps them clean upmore effectively, resulting in good regained permeability andconductivity. The present invention can be utilized in this situation;having a minimal negative effect on polymer chains. The latter isanother advantage of a preferred embodiment of the present invention.Borate crosslinked fluids have proved to be highly effective in both lowand high permeability formations.

To achieve an optimal crosslinking of borate crosslinked guar gel, a pHbetween 8.5 and 9.0 is necessary. This is a very narrow pH window. Acommon drawback of using neat caustic is that, as a strong base, a pH inthat range can be quite difficult to adjust. A slight difference indosage can result in a high pH shift, this results in the breakdown ofthe crosslinking in the gel.

In an attempt to overcome the drawback of using strong caustic agents inthe presence of crosslinked gels, or at least to compensate and create abuffer which allows some flexibility in the dosage, a crosslinker andguar gum is added on location on the fly with special equipment.

According to a preferred embodiment of the present invention, it isdesirable to have a buffered caustic solution, which enables one toadjust the pH more precisely in a desired range (in other words it ismore forgivable in terms of overdosage). Such a buffer provides asubstantial advantage over the use of a neat caustic composition

According to another preferred embodiment of the present invention, itis desirable to have a buffered caustic solution in water treatment.Caustics such as sodium hydroxide can be used to raise the pH of watersupplies. Increased pH renders the water less susceptible to corrodepipes and reduces the amount of free metals including copper and othermetals which can be found in drinking water.

Example 1 Preparation of a Composition

A composition according to the present invention was prepared byproviding 100 ml of 25 wt % NaOH solution. The NaOH solution is thenmixed with the appropriate weight of additive, in this case, 5% ofmonoethanolamine (MEA), to obtain the desired weight % concentration.Mixing the resulting composition until one visually determines thatsolubilization is complete.

Titration of the Composition

The titration of the composition of Example 1 was performed in order toassess its buffering ability. In order to do so, 1 ml of the buffer(composition of Example 1) was drawn and placed in a flask, the bufferwas then diluted in 100 ml of distilled water. The resulting solutionwas titrated with 1 N HCl standard. The pH was continuously recordedwith a pH meter. The solution was gently stirred with a magnetic stirbar during the measurements. Prior to recording the pH after eachaddition of HCl, sufficient time was given to allow for the pH tostabilize.

As can be seen by referring to FIGS. 1 to 2, a preferred embodiment ofthe present invention (set out in FIG. 2) displayed an extendedbuffering effect when exposed to acid addition as compared to causticcomposition free of additive. This extended buffering effect translatesinto an increased ability to control the pH of crosslinked gels duringfracking operations. This is even more advantageous when the pHadjustment is done on the fly. Preferred compositions of the presentinvention display a strong caustic character, an extended bufferingeffect (compared to neat caustic) and minimized dermal damage upondirect contact with human skin.

According to a preferred embodiment of the present invention, acomposition comprising a caustic component, an additive such as MEA andwater can buffer the pH drop of a 25 wt % caustic solution in the pHrange of 8.25 to 10. Such a buffering effect is desirable in frackingoperations to maintain the integrity of a guar gel based polymericsystem. Also desirable is the number of components in the composition.This type of composition is desirable as it necessitates very fewprocessing steps, which leads to decreased exposure to personnel.

According to another application of the composition according to thepreferred embodiment of the present invention, a hot solution of thecaustic composition according to a preferred embodiment of the presentinvention can be used to dissolve aluminium-containing minerals in thebauxite. This, as a result, forms a supersaturated solution of sodiumaluminate. When the solution is cooled it will yield a solid form ofsodium aluminate. This sodium aluminate can be employed in watertreatment, in construction to accelerate the solidification of concrete,in the paper industry, to make fire bricks production, to manufacturealumina.

According to another preferred embodiment of the present invention, itis desirable to have a buffered caustic solution in water treatment.Caustics such as sodium hydroxide can be used to raise the pH of watersupplies. Increased pH renders the water less susceptible to corrodepipes and reduces the amount of free metals including copper and othermetals which can be found in drinking water.

According to another application of the composition according to thepreferred embodiment of the present invention, there is provided amethod for treating mine water from an ore deposit, wherein the minewater contains sodium carbonate and sodium bicarbonate, the methodcomprising:

-   -   pumping the mine water from the ore deposit;    -   introducing a tailings stream comprising an amount of the        caustic composition according to a preferred embodiment of the        present invention into the mine water to form a reaction        solution;    -   maintaining a pH of between about 11.5 and about 13 in the        reaction solution;    -   separating a treated mine water from the reaction solution to        form a concentrate;    -   introducing the treated mine water into an alkali production        process.

According to a preferred embodiment of the present invention, acomposition comprising MEA can have a freezing point in a temperaturerange of around −45° C. This is a substantial decrease in the freezepoint compared to −18° C. for 25% NaOH. This proves to be highlydesirable for winter operations in the oil and gas industry.

According to a preferred embodiment of the present invention, there isprovided a method of fracking a hydrocarbon-bearing formation using acrosslinked polymer gel, said method comprising the steps of:

-   -   providing a hydrocarbon-bearing formation;    -   providing a polymer;    -   providing a cross-linking activator and adding such to the        polymer;    -   adding to the polymer mixture a caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended            buffering effect to the caustic composition when such is            exposed to acid; and        -   water;    -   adding a proppant to the resulting polymer mixture; and    -   injecting said resulting polymer-proppant composition into the        formation. Preferably, the caustic component is present in        amount of up to 50 wt % of the composition. Preferably, the        crosslinking component is selected from the group consisting of:        borate ions and zirconate ions. Preferably, the polymer is a        guar gum.

According to a preferred embodiment of the present invention, there isprovided a method of removing impurities present in petroleum during therefining thereof, said method comprising the steps of:

-   -   providing a petroleum product to be refined;    -   providing a caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended            buffering effect to the caustic composition when such is            exposed to acid; and        -   water;    -   adding said caustic composition to said petroleum product to be        refined; and    -   allowing said caustic composition and petroleum product to be        refined to remain in contact with one another for a period of        time determine to be sufficient for the sufficient removal of at        least one of carbon dioxide and sulfur-containing compounds.

According to a preferred embodiment of the present invention, there isprovided the use of a caustic composition according to the presentinvention, for the control of pH of drilling fluids.

According to another preferred embodiment of the present invention,there is provided the use of a caustic composition according to thepresent invention, for the breaking down of organic matter present inpetroleum during the refining thereof.

According to a preferred embodiment of the present invention, there isprovided the use of a caustic composition according to the presentinvention, for the removal of various impurities during the refiningstage of petroleum production. Preferably, the impurities are selectedfrom the group consisting of: carbon dioxide and sulfur-containingcompounds.

According to a preferred embodiment of the present invention, there isprovided a use of the composition according to present invention in aprocess for the treatment of water.

According to a preferred embodiment of the present invention, there isprovided an aqueous caustic composition comprising:

-   -   a caustic component;    -   an alkanolamine additive adapted to provide an extended        buffering effect to the caustic composition when such is exposed        to acid; and    -   water;        wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the alkanolamine additive are present in a molar ratio ranging        from 15:1 to 5:1. Preferably, the caustic component and the        additive are present in a molar ratio ranging from 12:1 to 8:1.        Preferably, the caustic component comprises: a hydroxide anion        and a monovalent cation.

According to a preferred embodiment of the present invention, there isprovided a use of a buffered caustic solution in water treatment,wherein said buffered caustic solution comprising:

-   -   a caustic component;    -   an alkanolamine additive adapted to provide an extended        buffering effect to the caustic composition when such is exposed        to acid; and    -   water;    -   wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the additive are present in a molar ratio ranging from 15:1 to        5:1;

According to a preferred embodiment of the present invention, there isprovided a method to treat water, wherein said method comprises thesteps of:

-   -   providing an aqueous caustic composition comprising:        -   a caustic component;        -   an alkanolamine additive adapted to provide an extended            buffering effect to the caustic composition when such is            exposed to acid; and        -   water;    -   wherein the caustic component is present in a concentration of        up to 40 wt % of the composition and the caustic component and        the alkanolamine additive are present in a molar ratio ranging        from 15:1 to 5:1;    -   exposing a water requiring treatment to a pre-determined amount        of said caustic composition for a period of time sufficient to        effect the treatment intended.

According to a preferred embodiment of the present invention, there isprovided a method for treating mine water from an ore deposit, whereinthe mine water contains sodium carbonate and sodium bicarbonate, themethod comprising:

-   -   pumping the mine water from the ore deposit;    -   introducing a tailings stream comprising an amount of the        composition according to the present invention into the mine        water to form a reaction solution;    -   maintaining a pH of between about 11.5 and about 13 in the        reaction solution;    -   separating a treated mine water from the reaction solution to        form a concentrate; and    -   introducing the treated mine water into an alkali production        process.

Although an embodiment was shown and described, it will be appreciatedto those skilled in the art that various changes and modifications canbe made to the embodiment described herein. The terms and expressionsused in the above description have been used herein as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding equivalents of the featuresshown and described or portions thereof, it being recognized that theinvention is defined and limited only by the claims that follow.

1. An aqueous caustic composition comprising: a caustic component; analkanolamine additive adapted to provide an extended buffering effect tothe caustic composition when such is exposed to an acid; and water. 2.The caustic composition according to claim 1, wherein the causticcomponent is selected from the group consisting of: potassium hydroxide;sodium hydroxide; lithium hydroxide; cesium hydroxide; rubidiumhydroxide; and combinations thereof.
 3. The caustic compositionaccording to claim 1, wherein the caustic component is selected from thegroup consisting of: potassium hydroxide; sodium hydroxide; andcombinations thereof.
 4. The caustic composition according to claim 1 toclaim 1, wherein the alkanolamine additive is selected from the groupconsisting of: monoethanolamine; diethanolamine; triethanolamine;aminomethyl propanol; propanolamine; dimethylethanolamine; andN-methylethanolamine.
 5. The caustic composition according to claim 1,wherein the alkanolamine additive is monoethanolamine.
 6. The causticcomposition according to claim 1, wherein the alkanolamine additive isdiethanolamine.
 7. The caustic composition according to claim 1, whereinthe alkanolamine additive is triethanolamine.
 8. The caustic compositionaccording to claim 1, wherein the caustic component is present in aconcentration of up to 40 wt % of the composition.
 9. The causticcomposition according to claim 1, wherein the caustic component ispresent in a concentration ranging from 5 to 40 wt % of the composition.10. The caustic composition according to claim 1, wherein the causticcomponent is present in a concentration ranging from 10 to 30 wt % ofthe composition.
 11. The caustic composition according to claim 1,wherein the caustic component is present in a concentration ranging from15 to 25 wt % of the composition.
 12. The caustic composition accordingto claim 1, wherein the caustic component is present in a concentrationof approximately 25 wt % of the composition.
 13. The caustic compositionaccording to claim 1, wherein the additive is present in a concentrationranging from 2 wt % to 25 wt % of the composition.
 14. The causticcomposition according to claim 1, wherein the additive is present in aconcentration ranging from 4 wt % to 15 wt % of the composition.
 15. Thecaustic composition according to claim 1, wherein the alkanolamineadditive is present in a concentration ranging from 4 wt % to 10 wt % ofthe composition.
 16. A method of fracking a hydrocarbon-bearingformation using a crosslinked polymer gel, said method comprising thesteps of: providing a hydrocarbon-bearing formation; providing apolymer; providing a cross-linking activator and adding such to thepolymer; adding to the polymer mixture a caustic composition comprising:a caustic component; an alkanolamine additive adapted to provide anextended buffering effect to the caustic composition when such isexposed to acid; and water; adding a proppant to the resulting polymermixture; and injecting said resulting polymer-proppant composition intothe formation.
 17. The method according to claim 16, wherein thecrosslinking component is selected from the group consisting of: borateions and zirconate ions.
 18. The caustic composition according to claim16, wherein the polymer is a guar gum.
 19. An aqueous causticcomposition comprising: a caustic component; an alkanolamine additiveadapted to provide an extended buffering effect to the causticcomposition when such is exposed to acid; and water; wherein the causticcomponent is present in a concentration of up to 40 wt % of thecomposition and the caustic component and the alkanolamine additive arepresent in a molar ratio ranging from 15:1 to 5:1.
 20. An aqueouscaustic composition according to claim 19 where the caustic componentand the additive are present in a molar ratio ranging from 12:1 to 8:1.21. An aqueous caustic composition according to claim 19 wherein thecaustic component comprises: a hydroxide anion and a monovalent cation.